Field of the Invention
The present invention relates to a wireless power transmission system, and more particularly, to a transmitter and a receiver in a wireless power transmission system capable of having high resonance characteristics and a wireless power transmission and reception method for the transmitter and the receiver.
Description of the Related Art
With the development of wireless communication technologies, a ubiquitous information environment is now provided in which anyone can exchange any desired information regardless of time and place. Even now, however, most communication information devices depend on batteries and are supplied with power through wired power codes, such that use of communication and information devices is limited. Therefore, a wireless information network environment cannot be free in the true sense without solving a problem regarding terminal's power.
To solve this problem, a lot of techniques for wirelessly transmitting power have been developed. Among them, a microwave reception-type technique using microwaves, a magnetic induction-type technique using a magnetic field, and a magnetic resonance technique based on energy conversion between a magnetic field and an electric field are representative techniques.
Herein, the microwave reception-type technique has an advantage of transmitting power a remote distance by radiating microwaves over the air, but due to large radiation loss caused by the microwaves consumed in the air, there is a limitation in the efficiency of power transmission. The magnetic induction-type technique is a technique which uses magnetic energy coupling based on a transmission-side primary coil and a reception-side secondary coil, and has a high efficiency of power transmission. However, for power transmission, the transmission side primary coil and the reception side secondary coil have to be adjacent to each other within a short distance of several mms therebetween. The efficiency of power transmission rapidly changes with coil alignments of the transmission-side primary coil and the reception-side secondary coil, and the amount of heat generation is large.
Therefore, a magnetic resonance technique has been recently developed, which is similar to the magnetic induction-type technique, but is such that energy is concentrated at a particular resonance frequency by a coil-type inductor (L) and a capacitor (C) to transmit power in the form of a magnetic energy. This technique, in spite of transmission of relatively large power several meters, requires a high quality factor. As a result, a design of a wireless power transmission system having high resonance characteristics is required.